Hot work, such as welding, at facilities where flammable and combustible materials are present, is extremely dangerous and is regulated by the appropriate governmental agency depending on the facility. In the case of offshore platforms, hot work is regulated by the Mineral Management Service (MMS); in the case of pipeline, pumping stations and associated facilities, hot work is regulated by the Department of Transportation (DOT) and in the case of refineries and chemical plants, hot work is regulated by the Occupational Safety and Health Administration (OSHA). Regulations stipulate that hot work cannot be preformed in or on any of said facilities within 35 feet from the point of impact where slag, sparks or other burning materials could fall onto or in the vicinity of a storage area of a container containing flammable or combustible materials. Also, hot work cannot be preformed within 10 feet of a pressurized pipe or vessel containing flammable or combustible material in or on any of said facilities.
In some cases, the hot work operation can be setup in a safe area and items to be hot worked can be brought to this safe area, hot worked, and then returned to their original location. In most cases it is not practical, from a strategic or from an economic point of view, to setup a remote hot work location a distance away from the item that needs to be hot worked. In the past, a facility such as a petroleum production platform, would have to be shut down during hot work operations. Further, a section of pipe or vessel in a petroleum refinery or chemical plant would have to be purged and cleaned of flammable and combustible material before any hot work could be performed within 10 feet of it. This created a substantial financial burden for the operator of the platform or plant.
A welding habitat was developed within the last few years wherein a temporary building was built around an object to be hot-worked. The habitat, also referred to as an enclosure, is equipped with gas detection monitors that would automatically signal a shut down of all welding equipment when a predetermined concentration level of flammable or combustible gas is reached. For example, U.S. Pat. No. 6,783,054 to Pregeant Jr. et al. teaches and claims a system for conducting welding adjacent flammable materials on an offshore platform. The system contains an enclosed chamber having a blower and sensors, each of which monitors a single gas, typically a combustible gas, and the ability to automatically shutdown the welding operation if a predetermined unacceptable concentration of a combustible gas is detected at one or more sensors.
Co-pending applications U.S. Ser. No. 10/388,271 filed Mar. 13, 2003 and U.S. Ser. No. 11/011,848 filed Dec. 14, 2004, both of which are incorporated herein by reference, teach a welding habitat and control and monitoring system wherein there is wireless communication between gas detection devices and a CPU monitored by an operator.
While the industry is starting to see habitat and monitoring systems that enable hot work to be preformed in areas here-to-fore not allowed unless the facility was shut-down, there is still a need in the art for improved hot work enclosures and monitoring and control systems that lead to a more economical and safe hot work operation.